Can peel and stick tiles be used on 1/2 bath ceiling?

Sure as long as perfectly smooth, clean and flat sheen finish

Check to make sure your glue/paste is waterproof, the steam will make them fall if it's not good luck

Peel and stick tiles are made to go on walls mainly for backsplashes. There ARE special peel and stick tiles made for ceiling application.

Here is a partial list of ideal surfaces for peel and stick tiles:

painted gypsum (the paint must have been applied at least 21 days before),

smooth ceramic tiles backsplash,

smooth glass tiles backsplash,

wall panel (acrylic),

wall linoleum,

mirror,

wallpaper (if some corners are peeling, just peel them off and install over them).

Not recommended:

stucco wall,

brick wall,

stone wall,

unfinished wall (gypsum or plaster),

unpainted plywood.

Also not recommended to install:

in the shower,

on the countertop,

on the floor,

on the ceiling.

Even with these constraints, peel and stick tiles can be installed in a bathroom, kitchen or on a fireplace mantel.